Martin K A, Grant S G, Hockfield S
Section of Neurobiology, Yale University School of Medicine, New Haven, CT 06510.
Brain Res Dev Brain Res. 1992 Jul 24;68(1):75-82. doi: 10.1016/0165-3806(92)90249-v.
The mas proto-oncogene encodes a protein with a predicted structure similar to members of the family of seven transmembrane domain spanning receptors. These receptors are thought to transduce extracellular signals to G-proteins. Angiotensin II and III have been reported to be the functional ligands for the mas oncogene-encoded receptor (Jackson et al., 1988). We show here using in situ hybridization histochemistry and RNase protection assays that mas mRNA is expressed in a subpopulation of neurons in both the adult and developing rat CNS. In the adult CNS, mas mRNA is most abundant in hippocampal pyramidal neurons and dentate granule cells; mas transcripts are also present at low levels in the cortex and thalamus. mas is first expressed in the developing rat CNS at postnatal day 1 (P1). Even at this early stage in CNS development the pattern of mas expression is similar to that seen in the adult. Although at P1 most neurons of the dentate gyrus are not yet generated and cells of the hippocampal CA fields are undergoing migration and synaptogenesis (Bayer 1980; Altman and Bayer, 1990a, 1990b, 1990c), mas is specifically expressed in these cell populations. This extremely restricted pattern of expression suggests that mas may function in determining the morphology and connections of specific cell types in the hippocampus. This function may in part be carried out by the ability of mas to link external cues to intracellular processes.
原癌基因mas编码一种蛋白质，其预测结构类似于七跨膜结构域受体家族的成员。这些受体被认为可将细胞外信号转导至G蛋白。据报道，血管紧张素II和III是mas原癌基因编码受体的功能性配体（杰克逊等人，1988年）。我们在此利用原位杂交组织化学和核糖核酸酶保护试验表明，mas mRNA在成年和发育中的大鼠中枢神经系统的一部分神经元中表达。在成年中枢神经系统中，mas mRNA在海马锥体细胞和齿状颗粒细胞中最为丰富；mas转录本在皮质和丘脑中也有低水平表达。mas在出生后第1天（P1）开始在发育中的大鼠中枢神经系统中表达。即使在中枢神经系统发育的这个早期阶段，mas的表达模式也与成年时相似。尽管在P1时齿状回的大多数神经元尚未生成，海马CA区的细胞正在进行迁移和突触形成（拜尔，1980年；奥尔特曼和拜尔，1990a、1990b、1990c），但mas在这些细胞群体中特异性表达。这种极其受限的表达模式表明，mas可能在决定海马中特定细胞类型的形态和连接方面发挥作用。这种功能可能部分是通过mas将外部信号与细胞内过程联系起来的能力来实现的。
